Inspection Procedure 12

INSPECTION PROCEDURE 12: No Diagnostic Trouble Codes (Does not Shift) Backup Power Supply System Circuit

Part 1 Of 2:

Part 2 Of 2:

CIRCUIT OPERATION
PCM (terminal number 66) receives battery positive voltage from the battery.

COMMENT
If shifting does not occur while driving and no diagnostic trouble codes are output, a malfunction of the transmission range switch, or PCM may exist.

TROUBLESHOOTING HINTS (The most likely causes for this case:)
^ Malfunction of the transmission range switch
^ Damaged harness, connector
^ Malfunction of the PCM

DIAGNOSIS

Required Special Tool:
^ MB991958: Scan Tool (MUT-III Sub Assembly)
^ MB991824: V.C.I.
^ MB991827: MUT-III USB Cable
^ MB991911: MUT-III Main Harness B

STEP 1. Check the vehicle acceleration.
Q: Does the vehicle accelerate poorly (transaxle stays in 3rd gear) when starting from a stop with the selector lever in "D" range?
YES: Go to Step 2.
NO: Go to Step 5.

STEP 2. Measure the backup power supply voltage at PCM connector C-54 <2.4L Engine> or C-55 <3.0L Engine> by backprobing.





1) Do not disconnect connector C-54 <2.4L Engine> or C-55 <3.0L Engine>.





2) Measure the voltage between terminal 66 and ground by backprobing.
^ The voltage should be measured battery positive voltage.
Q: Is the measured voltage battery positive voltage?
YES: Go to Step 5.
NO: Go to Step 3.

STEP 3. Check intermediate connector C-07 and PCM connector C-54 <2.4L Engine> or C-55 <3.0L Engine> for loose, corroded or damaged terminals, or terminals pushed back in the connector.








Q: Are the connectors and terminals in good condition?
YES: Go to Step 4.
NO: Repair or replace the damaged components. Then check for the symptom.

STEP 4. Check the harness for open circuit between PCM connector C-54 <2.4L Engine> or C-55 <3.0L Engine> terminal 66 and battery.





Q: Is the harness wire in good condition?
YES: Go to Step 5.
NO: Repair or replace the harness wire.

STEP 5. Using scan tool MB991958, check data list item 61: Transmission Range Switch.

CAUTION: To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.





1) Connect scan tool MB991958 to the data link connector.
2) Turn the ignition switch to the "ON" position.
3) Set scan tool MB991958 to data reading mode for item 61: Transmission Range Switch.
^ Move the selector lever to "P," "R," "N," "D," "3," "2," "L" positions and confirm that the selected selector lever positions match the positions shown on the scan tool MB991958.
4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the switch operating properly?
YES: Check for the symptom. If the symptom is not eliminated, replace the PCM.
NO: Refer to DTCs 27, 28: Transmission Range Switch System.